Voltage regulator



Dec. 13, 1927. L652,923

E. F. w, ALEXANDERSON VOLTAGE REGULATOR Filed March -17 1926 mgi l0 Inventor: Ernst F W Alexander-son, by M His AUGSTTW g.

Patented Dec. 13, 1927.

UNITED STATES PATENT OFFICE.

ERNST F. W. ALEXANDERSON, OF SCHENECTAD'Y, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

VOLTAGE REGULATOR.

Application filed March 17, 1926. Serial No. 95,458.

My invention relates to apparatus for regulating the voltage of an electrical circuit, and has for its principal object the provision of an improved voltage regulator that comprises no moving parts and is both sensitive and reliable in its operation.

Various types of devices have been utilized in the past for regulating the voltage, or another electrical condition, of a circuit. Many of these devices are not altogether satisfactory in their operation for the reason that they respond somewhat sluggishly to variations in the condition to be regulated and are incapableof maintaining such variations within the limits required for the best operation of the circuit. In accordance with my invention, variations in the electrical conditions of the circuit to be regulated are maintained within narrow limits by a regulating apparatus comprising a variable impedance device connected to the circuit and arranged to have its impedance regulated by thermionic means operable in accordance with variations in the circuit conditions.

My invention will be better understood from the following description when considered in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

Referring to the drawings, Fig. 1 shows a regulating apparatus wherein my invention has been embodied; and Fig. 2 shows a modified embodiment of the regulating apparatus.

Fig. 1 shows a current supply circuit 1 and a distribution circuit 2 which are interconnected through a regulating apparatus comprising a series impedance coil 3, a shunt impedance device 4 and a thermionic device 5. The impedance device 4 comprises a core 6 upon which are wound an impedance or regulating coil 7 connected in shunt to the circuit 2, a coil 8 through which heating current is supplied to the cathode 9 of the device 5, and a coil 10 which is connected between the cathode 9 and anode 11 of the device 5.

With these connections, the cathode heating current and anode potential of the thermionic device 5 are varied in accordance with the voltage applied to the circuit 2, and the impedance of the device 4 is controlled by the direct current transmitted through the winding 10 and the device 5. If the voltage of the circuit 2 tends to increase, for example, more electrons are emitted at the cathode 9, the current of the saturation coil 10 is increased and the impedance of the device 4 is correspondingly reduced, thus causing the excess voltage of the line 1 to be applied to the series reactor 3 instead of to thecircuit 2. If the voltage of the circuit 2 tends to decrease, the impedance of the device 4 is increased, and large changes in this voltage are avoided. The operation of the regulating apparatus described will lnvolve slight variations in the voltage of the circuit 2, but these variations will be so small compared to voltage variations of the supply circuit 1 as to be negligible. These small variations in voltage may be obviated by IBnodigying the apparatus as indicated by Fig. 2 shows a regulating apparatus which differs from that of Fig. 1 in that an additional coil 12 wound on an open core 13 together with the reactance coil 3 is connected to the anode circuit of the device 5 in series with the saturation coil 10. A differential coil 14 wound on the core 6 and connected in series relation with the circuit 2 through a current transformer 15 also may be provided for minimizing voltage changes due to variation in the load of the circuit 2. The opening in the-core 13 is provided for preventing saturation. of the series reactance device.

As previously explained, the devices 4 and 5 function to cause any excess voltage of the line 1 to be applied to the series impedance coil 3, thus maintaining the voltage of the distribution circuit 2 substantially constant. WVith the coil 12 wound on the same core as the series impedance coil 3, the increase in voltage applied to the coil 3 will tend to further increase the current of the saturation coil 10. Thus there is a tendency for the rectified saturation current to increase, both due to the larger heating current of the cathode 9 and to the higher voltage applied to the anode circuit of the device 5. These factors can be readily balanced in such a way that the distribution circuit voltage and the current of coil 7. When the load of the circuit 2 is increased, the series transformer 15 produces through the differential Winding 14 a flux which is opposed to that produced by the shunt impedance coil 7, and the impedance of the device 4 is maintained at a value which tends to compensate for the voltage drop occasioned by increase in the load of the circuit 2.

The embodiments of the invention illustrated and described herein have been selected for the purpose of clearly setting forth the principles involved. It will be apparent, however, that the invention is susceptible of being modified to meet the different conditions encountered in its use, and I, therefore, aim to cover by the appended claims all modifications within the true spirit and scope of my invention. 5

What I claim as new, and desire to secure by Letters Patent of the United States, is:

1. The combination of a circuit, a device comprising an impedance coil connected to said circuit, and means comprising a thermionic device arranged to regulate the impedance of said coil in response to variation in the voltage of said circuit.

2. The combination of a circuit, a thermionic device comprising a cathode and anode, and a device comprising a core, an impedance winding connected to said circuit and wound on said core, and a winding connected between said cathode and anode and wound on said core for regulating the impedance of said impedance winding in response to variation in voltage of said circuit.

3. The combination of a supply circuit, an impedance device comprising a winding, a distribution circuit connected to said supply circuit through said winding, a thermionic device provided with a cathode and anode, and a device comprising a core, an impedance winding connected in shunt to said distribution circuit and wound'on said core, a winding connected to said cathode for controlling the cathode heating current, and a winding connected between said cathode and anode and wound on said core for regulating the impedance of said shunt connected winding in response to variation in the voltage of said distribution circuit.

4:. The combination of a supply circuit, a series impedance device comprising an open core and a pair of windings, a distribution circuit connected to said supply circuit through one winding of said pair, a thermionic device provided with a cathode and anode, and a shunt impedance device comprising a core, an in'ipedance winding connected in shunt to said distribution circuit and wound on said core, and a winding wound on said core and connected between said cathode and anode in series with the other winding of said pair for regulating the saturation of the core of said series impedance device in response to variation in the voltage of said distribution circuit.

5. The combination of a supply circuit, an impedance device comprising a winding, a distribution circuit connected to said supply circuit through said winding, a thermionic device provided with a cathode and anode, and an impedance device comprising a core, a winding wound on saidcore and connected in shunt to said distribution circuit, a winding connected to said cathode for controlling the cathode heating current, a winding wound on said core and connected between said cathode and anode for regulating the impedance of said shunt connected winding in response to variation in the voltage of said distribution circuit, and a differential winding connected in series relation with said distribution circuit.

In witness whereof I have hereunto set my hand this 15th day of March, 1926.

ERNST F. \V. ALEXANDERSON. 

